REFRACTORY-METAL THERMOCOUPLES IN NUCLEAR AND HIGH-TEMPERATURE APPLICATIONS (Task 6)

摘要

The performance of platinum, tungsten, tungsten-rhenium alloys, and molybdenum-rhenium alloys in thermocouples in nuclear reactor and high-temperature environments was investigated, using BeO, ThO2, and Y2O3 as insulators and tantalum, niobium, and molybdenum as sheaths. Upon irradiation of thermoelement wires at 50 C both transmutation and displacement effects were found, although displacement damage showed signs of annealing out during testing at 1000 C. Transmutation effects, due mainly to the production of osmium from rhenium were small, and are probably insignificant except in long-term use.